November 17, 2005
01:00 PM (EST)

News Release Number: STScI-2005-32

Hubble, Sloan Quadruple Number of Known Optical Einstein Rings

November 17, 2005: Astronomers have combined two powerful astronomical assets, the Sloan
Digital Sky Survey (SDSS) and NASA's Hubble Space Telescope, to identify
19 new "gravitationally lensed" galaxies, adding significantly to the
approximately 100 gravitational lenses previously known. Among these 19,
they have found eight new so-called "Einstein rings," which are perhaps
the most elegant manifestation of the lensing phenomenon. Gravitational
lensing occurs when the gravitational field from a massive object warps
space and deflects light from a distant object behind it. Einstein rings
are produced when two galaxies are almost perfectly aligned, one behind
the other.

The thin blue bull's-eye patterns in these eight Hubble Space Telescope
images appear like neon signs floating over reddish-white blobs. The blobs
are giant elliptical galaxies roughly 2 to 4 billion light-years away. The
bull's-eye patterns are Einstein rings, which are created as the light from
galaxies twice as far away is distorted into circular shapes by the gravity
of the giant elliptical galaxies.